A close encounter of the planetary kind is on tap for early December. In the hour just before sunrise on December 10 as the sky is brightening, three planets hover near the horizon: Mercury, Mars, and Jupiter. The three solar system bodies will form a tight triangle within one degree of each other. A gathering of three naked-eye planets in such close quarters has not occurred since 1980 and will not occur again until 2050.
Although these planets are usually seen with the naked eye, because this incident occurs so close to sunrise, it's best to try to locate them first with a pair of binoculars and then try to fix them with your eye alone. Jupiter will be the brightest of the three planets at magnitude -1.7. It will also be the one closest to the horizon. Next look for Mercury, the second lowest object and shining at a magnitude of -0.6. Lastly is Mars, the planet marking the top of the triangle, shining at magnitude 1.5.
You can start watching for the great meeting of the planets on December 6. The three planets will span 5.3 degrees in the morning. Mercury is highest in the sky, then Mars followed by Jupiter closest to the horizon. Mars and Jupiter are rising with the Sun, with Mercury sinking back toward the Sun. Jupiter is moving faster than Mars, so by the time the conjunction is over by December 16, Jupiter will then be the highest of the three planets with Mercury closest to the horizon.
Look just a little bit south of due east to see this planetary conjunction. The planets will be just five degrees above the horizon, so make sure you have a clear view to the east. On December 11, the three planets will overall be a bit farther from each other, but they will lie in an up-and-down line, with Jupiter and Mercury a mere 8 arcminutes apart.
If you are still watching on the morning of December 13, you get a second treat. The Geminid meteor shower peaks. The Geminid meteor shower is not the debris of a comet, as most other meteor showers are, but the debris of an asteroid named 3200 Phaethon.
Happy Observing!
Read my observing log of this event.
Learn about the best Planetary Conjunctions of 2008.
Kelly Whitt - I have been a professional writer for more than a decade, covering many topics from science-based articles to do-it-yourself home ...
